At the present time, a decrease in the size of electronic devices are demanded more and more, the sizes of electronic components mounted on the electronic devices are decreased, so that the electronic components are arranged closer to each other. When such electronic components are arranged close to each other, noise generated in an electronic component may be transmitted to other electronic components directly or through a mounting board or wires and may hinder normal operations of the other electronic components. Accordingly, suppression of an influence of noise along with a decrease in size are requested for electronic devices these years (hereinafter, referred to as anti-noise measures).
In order to prevent noise generated in an electronic component from influencing on other electronic components, it is generally conceivable that electronic components are arranged so as to be separated from each other to such an extent to reduce the influence of noise or arrangement or separation of elements is designed in processes of manufacturing the electronic components. It is also conceivable that input and output terminals are independently provided for individual electronic components.
However, the arrangement of the electronic components to be separated from each other hinders a decrease in the size of the electronic devices, which is not preferable. In order to prevent noise from influencing on the outside through the use of processes of manufacturing the electronic components, advanced process technology is needed and the manufacturing cost is increased as a result, which is not preferable. Division of the input terminal or the output terminal increases the number of pins of the electronic devices and is disadvantageous for decreasing the size of the electronic components.
Examples of the electronic components mounted on the electronic devices include a D/A converter and an A/D converter. The D/A converter and the A/D converter are electronic components widely used for audio functions of the electronic devices and are electronic components particularly necessitating the anti-noise measures.
As a technique for the anti-noise measures of the D/A converter and the A/D converter, for example, the invention described in Patent Document 1 is known. In the invention described in Patent Document 1, jitter is added to a synchronization signal (control clock signal) of an input signal of the D/A converter or the A/D converter. According to the invention described in Patent Document 1, it is possible to spread radiation of beat noise due to a synchronization signal (conversion clock signal) used to output an output signal and the control clock signal.
Such conventional techniques were invented on the basis of a thought that radiation noise generated from the A/D converter or the D/A converter is reduced to reduce an influence of noise on other equipment.